Human retroviruses, as a family, represent a group of related exogeneous retroviruses which exert a significant proliferative or cytopathic effect upon the target T-lymphocytes they infect. The resulting effects of these retroviruses include T-cell proliferation leukemia, T-cell depletion and immunosuppression in humans infected by the viruses. These retroviruses are known as the HTLV (human T-cell leukemia-lymphoma virus) and HIV (human immuno-deficiency virus) families of T4 tropic retroviruses.
The first human retrovirus discovered, HTLV-I, appears to represent the etiological agent of mature T-cell leukemias and lymphomas as typified by Adult T-cell leukemia. See, for example the investigations reported by Poiesz et al, Proc. Nat. Acad. Sci. U.S.A., 77, 1980 and Yoshida et al, supra, 79, 1982. At present, the presence of HTLV-I and T-cell malignancies are believed to occur at increased rates in the populations of certain Caribbean islands and southern Japan, but HTLV-I is now widely recognized as a worldwide medical concern. People infected with HTLV-I or having come into contact with the virus generally have antibodies directed against HTLV-I in their body fluids, especially in their blood. In addition, a significant portion of the patients suffering from the neurological disorder known as Tropical Spastic Paraparesis possess antibodies to HTLV-I.
Continuing research has determined that there are several additional retroviruses which are of significant medical importance. A third retrovirus isolated and characterized has been variously identified as HTLV-III, Lymphadenopathy Associated Virus (LAV) and AIDS Related Virus. It has been implicated as the etiological agent responsible for Acquired Immune Deficiency Virus (AIDS). See, for example U.S. Pat. No. 4,520,113 (issued May 28, 1985 to Gallo et al). In order to reduce confusion, the scientific community has recently renamed the group of viruses as the Human Immunodeficiency Viruses.
As for other viral diseases, exposure to and infection from any of HTLV or HIV produces an immune response, that is the production of antibodies. More specifically, antibodies to antigens of the viruses have been detected by researchers and clinicians in many sero-epidemiologic studies. The presence of either HTLV-I or HIV-I viral-specific gene sequences in infected cells has also been confirmed using DNA probe technology. Both lines of evidence indicate that transmission of either virus can occur either by vertical or horizontal transmission. Human biological fluids, such as whole blood or components thereof, seminal fluid, saliva, lacrimal fluid and vaginal secretions, are considered as potential vectors for spreading such viruses. Blood samples are particularly likely vectors for virus transmission.
In order to reduce the risk of transmission of HIV-I, all blood banks currently screen blood obtained from all donors for the presence of antibodies against HIV-I. A number of useful screening assays have been developed some of which are described in U.S. Pat. No. 4,520,113 (noted above) and in E.P. Publications 136,798 (Biotech Research) and 216,191 (Abbott). In addition, assays for HTLV-I have been described in E.P. Publications 135,352 (Ajinomoto) and 136,798 (noted above). It is possible that routine screening of blood or other biological fluids for HTLV-I antibodies will also be desired in the future. E.P. Publication 173,295 (N.Y. Blood Center) describes a process for the simultaneous detection of the presence of an antigen and an antibody.
Current technology for testing biological fluids for both HTLV-I and HIV-I antibodies requires the use of two separate tests, one for each viral antibody. This necessitates purchase of two different test kits, possibly from different vendors, and may require different analytical equipment for determination in each test. The use of two separate tests increases testing time as well as purchase and screening costs. In addition, running two separate tests requires a larger sample of the biological fluid and extra handling which can result in procedural error as well as the dangerous possibilitty of contamination of the environment or other materials from spillage or insufficient housekeeping procedures.
It would be highly desirable to be able to routinely screen biological samples, such as blood samples, for pairs of antibodies from the highly infectious HTLV and HIV virus families in an inexpensive, rapid, safe and accurate manner.